Change logic checking shipping methods when orders come out of ONBACKORDER

Scenario:

An order imports into the system but the client has changed the rate name in Shopify so the order fails to assign a courier from the 'Courier Service Mapping' section

This is spotted and the relevant 'Courier Service Mapping' rule is added

Stock is booked in and the order moves from ONBACKORDER to NEW but no courier is assigned.

I've been told that as it has failed on the way in, the system will look at 'Courier Service Selection' but won't look again at 'Courier Service Mapping'.

If you select 'Recalculate Courier Method' from BulkActions, the courier is assigned but that is a manual process. Surely the system should be looking at both methods of assigning an order, not ignoring one.

Otherwise every few hours every day you have to run the manual process which is just madness. If one process looks at both elements, why is another only looking at one?